Synthesis of Azido Derivatives of Mucobromic Acid: Critical Study

Mucobromic acid is a highly reactive multicentered molecule. It was converted to its corresponding but
unstable diazido derivative by reaction with two equivalents of sodium azide. The resultant 3,4-
diazido-5-hydroxyfuran-2(5H)-one was obtained in moderate yield (42%) but decomposed readily
even at low temperatures. Its more stable analogue 3,4-diazido-5-methoxyfuran-2(5H)-one was
obtained in excellent yield after reacting 5-methoxy-3,4-dibromofuranone with two equivalents of
sodium azide. The 4,5-dibromopyridazinones which are in effect masked mucobromic acid
derivatives, underwent nucleophilic substitution reactions with various nucleophiles, including azides
and afforded corresponding azidopyridazinones in good yields. The synthesized azido-furanone and
pyridazinone derivatives are earmarked for click reactions.